Add installation and packaging targets

[AbdulRehman-Fayyaz]

Description

This PR implements CMake install targets and CPack configuration to generate .tar.gz and .deb packages. It also includes a fully automated Docker workflow (Bonus Task).

Changes

• Install Targets: Executable in bin/, library in lib/, headers in include/cpackexamplelib.
• CPack: Added cmake/CPackConfig.cmake with CPACK_DEBIAN_PACKAGE_SHLIBDEPS for auto-dependency generation.
• Bonus Task: Updated Dockerfile and added entrypoint.sh to build cpackexamplelib as SHARED and auto-generate packages.

How to Test (Bonus Task)

Run the following to automatically build and save packages to your host directory:

docker build -t cpack-exercise .
docker run --rm --mount type=bind,source="$(pwd)",target=/mnt/cpack-exercise cpack-exercise